Data decompression refers to the conversion of the compressed data bitstream to the original bitstream (or, in the case of partial decompression such as in multi-layer or multi-technique compression, a partially compressed version of the bitstream). Lossless data compression refers to a technique by which a data bitstream can be stored in a compressed bitstream consisting of fewer bits than the original bitstream. Importantly, the original data bitstream can be perfectly recovered from the compressed data bitstream.
The figures are not to scale. Wherever appropriate, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts.